IGF-1 is an endocrine growth mediator. It is the main effector of the growth hormone. IGF-1 also plays a part in the complex system of regulation of immunity and of inflammation on the sides of cytokines, of hormones (in particular cortisol, the growth hormone).
U.S. Pat. No. 5,202,119 describes the therapeutic use of human IGF-1 as an immunity stimulant in man and, more particularly, in immunodeficient individuals. A particular application is the combination of human IGF-1 with an immunogen to stimulate the production of antibodies to this immunogen. This patent aims to extend the application to mammals in general and to the avian species, but without describing animal IGF-1 sequences or providing the results of experiments on animals.
The Applicant has found that IGF-1 stimulates more particularly the cellular response in general. This response profile has turned out to be particularly well adapted in the case of feline retroviruses. It also stimulates mucosal immunity.
Until the invention, moreover, the gene encoding feline IGF-1 was not available.